Re: Escaping Data Rot

["Tristan" <tristan@a2central.com.remove-ylg-this>]

On Tue, 23 Mar 2010 20:48:11 -0400, Steven Hirsch wrote:

> D Finnigan wrote:
>> Michael J. Mahon wrote:
>>> A corollary is that the best backup medium for a hard disk is another
>>> hard disk.  It is much cheaper and infinitely more convenient to do a
>>> disk-to-disk copy than to play with changing removeable optical disks.
>>>
>>>
>> Agreed. I've always had the notion that the safest place to store
>> digital data is on a hard disk system. It's sealed, secure, and
>> high-capacity. Of course, tape can have a nice long life-span as well.
> 
> No spinning storage device comes within an order-of-magnitude of
> commercial tape media (e.g. LTO-2,3,4) in terms of durability and
> lifespan. There's a good reason that literally all enterprise-level
> backup schemes use tape libraries instead of a rack of drives.
> 
> Prices for used LTO-2 drives and tapes have hit the "sweet spot" in the
> past year.  I can backup my entire server (300GB RAID-5 array) on a
> single tape in less than an hour.  The tape goes in my briefcase and
> travels to the office with me  so there's always an off-site copy.
> 
> And I'll second the warnings about recordable optical media.  NEVER
> confuse a CD or DVD with an archival backup!  You may live to regret
> it...
> 
> Steve

Your words are true unfortunately. CD/DVD discs make lousy archival 
media. I have noticed archival CDs with a 300 year guarantee (I'd love to 
see someone make a claim on that) and DVDs with 100 years.

Hard discs make terrible archival media.
I have lost a lot of stuff to unexpected failures. Even my PC which 
hadn't been powered up for 6 months refused to boot from the hard disk.

It may be speculation but I believe one of the safest forms of media are 
SSDs. ICs are nearly immortal, they have no moving parts to get damaged, 
no exposed surfaces to get contaminated or oxidise, no platters (platen?) 
to get warped / scuffed. The only issue is that the data very slowly 
sinks into oblivion if it is left untouched.

When I get the time I'll have a dig for the .dsk images (that's the 
answer to whoever it was. I'm not compressing them) and... I don't know 
what to be honest.

Tristan.